Clinicopathological Characteristics Of Squamous Cell Carcinoma Of The Lung With Programmed Cell Death Ligand 1 (Pd-L1) Protein Expression.

7554 Background: PD-L1 expression by immunohistochemistry (IHC) reportedly predicts patient response to anti-PD-1/PD-L1 therapies in early phase clinical trials for solid tumors. However, there is limited data on the patient/tumor characteristics associated with PD-L1 expression in squamous cell carcinoma of the lung (SqCC). Methods: PD-L1 (E1L3N, 1:200, Cell Signaling Technology), PTEN, and CD8 IHC were performed on tissue microarrays of resected SqCCs (n = 162). Subsets of patients underwent clinical molecular (SNaPshot) and FISH testing. Cases with 10% or more tumor cells exhibiting negative or reduced PTEN expression were considered to have PTEN loss. PD-L1 expression in tumor cells and CD8 expression in tumor infiltrating lymphocytes (TILs) were semiquantitatively evaluated. PD-L1 expression, defined as 5% or more of the tumor cells exhibiting membranous staining, was correlated with clinicopathological and molecular features as well as patient outcomes. Results: The study cohort consisted of 96 Stag...